Low metal loaded, catalyst compositions including acidic mixed metal oxide as support

ABSTRACT

The invention provides a catalyst composition composed of a support portion and a catalyst portion. The support portion includes an acidic mixed metal oxide including a transitional alumina and a second metal oxide. The transitional alumina can comprise delta or theta alumina, in combination with other transitional phases, or an alpha or gamma alumina. The second metal oxide has a weight percentage that is less than the weight percentage of alumina. The catalyst portion is 25 weight percent or less of the catalyst composition and is composed of nickel and rhenium. The catalyst portion includes nickel in an amount in the range of 2 to 20 weight percent, based upon total catalyst composition weight, and there is no boron in the catalyst portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit from U.S. Provisional patent applicationhaving Ser. No. 61/195,455 (filed on Oct. 6, 2008) and entitled LOWMETAL CATALYST COMPOSITIONS INCLUDING ACIDIC MIXED METAL OXIDE ASSUPPORT, the disclosure of which is incorporated herein by reference.

FIELD

The invention relates to catalyst compositions that include low levelsof metals. More particularly, the invention relates to nickel-rheniumcatalysts on an acidic mixed metal oxide support. The acidic mixed metaloxide support includes transitional alumina. The inventive catalysts canbe used in transamination reactions to produce ethyleneaminecompositions having lower levels of cyclic components.

BACKGROUND

Linear ethyleneamines are known for their many uses in industry. Forexample, ethylenediamine (EDA) (1,2-diaminoethane) is a strongly basicamine in the form of a colorless liquid having an ammonia-like odor. EDAis a widely used building block in chemical synthesis, withapproximately 500,000,000 kg being produced in 1998. EDA is used inlarge quantities for production of many industrial chemicals, such asbleach activators, fungicides, chelating agents, plastic lubricants,textile resins, polyamide resins, and fuel additives. Diethylenetriamine(DETA) can be used primarily as an intermediate to manufacturewet-strength paper resins, chelating agents, ion exchange resins, oreprocessing aids, textile softeners, fuel additives, and corrosioninhibitors. Triethylenetetramine (TETA) has such major applications asepoxy curing agents, as well as the production of polyamides and oil andfuel additives.

It is recognized that linear polyalkylene polyamines (such as EDA, DETAand TETA) do not have the same industrial uses and demands as cyclicpolyalkyleneamines such as piperazine (PIP). As such, it can bedesirable to develop a process with sufficient selectivity in forming alinear polyalkylene polyamine to produce an amine composition with arelatively high ratio of a desired linear polyamine (e.g., DETA) to PIP.

One approach in producing linear ethyleneamines is reductive amination.Reductive amination (also known as reductive alkylation) involvesreacting an amine or ammonia with a carbon-containing material.Reductive amination involves the conversion of a carbonyl group(typically a ketone or an aldehyde) to an amine. A classic namedreaction is the Mignonac Reaction (1921) involving reaction of a ketonewith ammonia over a nickel catalyst, for example, in a synthesis ofalpha-phenylethylamine starting from acetophenone.

Reductive amination produces a variety of products, some of which havegreater economic value than others, depending upon current marketrequirements. For example, the reductive amination of monoethanolamine(MEA) produces lower molecular weight linear ethyleneamines, such asEDA, aminoethylethanolamine (AEEA), and DETA. A minor amount of higherlinear ethyleneamines, for example TETA and tetraethylenepentaamine(TEPA) are also formed. In addition, cyclic ethyleneamines, such as PIP,hydroxyethylpiperazine (HEP), and aminoethylpiperazine (AEP) are alsoformed. Cyclic ethyleneamines tend to be less valuable than acyclicethyleneamines. Accordingly, for maximum economic benefits the catalystcompositions used in commercial reductive amination processes should beselective to the desired mixture of amine products, in addition to beinghighly active.

It is appreciated in reductive amination art that reductive aminationcatalysts must first be reduced before effecting the reaction, and thenhydrogen gas employed during the course of the reaction in order tomaintain catalytic activity and selectivity. During the reaction,reductive amination typically requires addition of ammonia.

One drawback relating to the catalysts and processes that have beendescribed for reductive amination to produce linear polyamines is thatthey do not typically provide high selectivity to DETA. In theseprocesses, as MEA conversions are increased to produce more DETA, PIPproduction becomes a significant problem. PIP can be formed from ringclosure of DETA or AEEA. Catalysts that are promoted with preciousmetals are known to show improved activity and selectivity for thereductive amination of MEA to EDA; however, high levels of DETA in theproduct mix result in concurrent high levels of PIP. As a result, thereis still a need for improved catalysts which give high EDA and DETAselectivities while minimizing the amount of PIP formed in the productmixture.

The reductive amination of lower aliphatic alkane derivatives, i.e.,diols such as ethylene glycol and alkanolamines such as MEA, is acommercially important family of processes. A variety of catalystcompositions for this purpose is found in the literature and is usedcommercially. Many of these catalyst compositions are based onnickel/rhenium mixtures (such as nickel/rhenium/boron catalystcompositions and the like) deposited on a support material.

As an alternative to reductive amination, linear polyamines can beprepared by transamination. Transamination is a transfer of an aminogroup from one chemical compound to another, or the transposition of anamino group within a chemical compound.

Many of the catalysts disclosed for transamination are high metal loadedcatalysts. Specifically, Raney nickel catalysts have been employed.These catalysts typically have small particle sizes, which makes theiruse in fixed bed processes difficult. To address difficulties with smallparticle sizes, more recent approaches have involved associating thecatalytic metals with a support. However, such supported catalysts havetypically included very large catalytic metal loading, and such highcatalytic metal loading can create its own drawbacks. For example, U.S.Pat. No. 7,053,247 (Lif et al.) describes particulate catalystscontaining 26 to 65% by weight of nickel on an oxide carrier. Catalystcompositions including such high levels of catalytic metals can bepyrophoric, more expensive, and do not appear to offer highselectivities for desirable transamination products (e.g., DETA).

Transamination reactions are typically performed at lower temperaturesthan reductive amination. A general problem in transamination processesof EDA to DETA and higher polyethylenepolyamines is the fact that atmoderate temperatures and pressures, these processes can result in toohigh a proportion of cyclic ethyleneamine compounds, such as PIP, whichrequires that the EDA conversion be kept low.

SUMMARY

In accordance with aspects of the invention, catalyst compositionsuseful for transamination of amine-containing solutions are provided.Advantageously, the catalyst compositions can allow for the manufactureof desirable products such as EDA and DETA without generating largeamounts of cyclic products such as PIP and AEP. It has been found thatcatalyst compositions having acidic mixed metal oxide supports inaccordance with inventive principles, can provide improved selectivityin transamination reactions. Such improved selectivity can be describedas a preference for linear (acyclic) polyamines over cyclic polyamines.In some aspects, the inventive catalyst compositions can also provideimproved activity in transamination reactions. For example, in someembodiments, inventive catalyst compositions can be utilized at a lowerreaction temperature, where activity of the catalyst can be preserved.Moreover, the inventive catalyst compositions can include a lower metalloading, which can reduce costs.

Generally speaking, the invention provides a catalyst compositioncomprising a support portion comprising an acidic mixed metal oxide thatincludes a transitional alumina and a second metal oxide; and a catalystportion comprising nickel and rhenium, and optionally a promoter.Regarding the support portion, the transitional alumina can comprisedelta or theta alumina, alone or in combination with anothertransitional phase, an alpha alumina, and/or gamma alumina. The secondmetal oxide has a weight percentage that is less than the weightpercentage of alumina. In some aspects, the support portion comprises atleast 50 weight percent transitional phase alumina.

Regarding the catalyst portion, the catalyst portion is 25 weightpercent or less of the catalyst composition, the catalyst portioncomprises nickel in an amount in the range of 2 to 20 weight percent,based upon total catalyst composition weight, and there is no boron inthe catalyst portion.

The second metal oxide can comprise at least one element selected fromGroup IIA, IIIA, IVA, VA, VIA, IIB, IIIB, IVB, VB, VIB, VIIB and a rareearth element of the Periodic Table. In some embodiments, the secondmetal oxide is selected from silicon, lanthanum, magnesium, zirconium,boron, titanium, niobium, tungsten and cerium. In some illustrativeembodiments, the second metal oxide comprises silicon.

In some aspects, the support portion can comprise at least 50 weightpercent transitional alumina, or at least 90 weight percent transitionalalumina. When present, alpha alumina and/or gamma alumina can beincluded in an amount less than 50 weight, based upon the weight of thealumina support portion. As discussed herein, the amount of the variousphases of alumina can be selected to provide a support portion having adesired surface area, such as in the range of about 10 m²/g to about 200m²/g.

In some aspects of the invention, the second metal oxide can be presentin the support portion in an amount in the range of 5 weight percent to50 weight percent, based upon the weight of the support portion. Inillustrative embodiments, the support portion comprises the second metaloxide in an amount in the range of 5 weight percent to 35 weightpercent, based upon the weight of the support portion.

The support portion of the catalyst composition can be provided with adesired surface area. In some embodiments, the support portion has asurface area in the range of about 10 m²/g to about 200 m²/g, or in therange of about 40 m²/g to about 180 m²/g, or in the range of about 80m²/g to about 180 m²/g. Further, the support portion can be providedwith a morphology that minimizes as much as possible mass transferresistance. In some embodiments, the catalyst composition can beprovided with a morphology that reduces or minimizes mass transferresistance.

In accordance with inventive concepts, the catalyst portion can make up25 weight percent or less of the catalyst composition. In furtherembodiments, the catalyst portion is in the range of 3 weight percent to20 weight percent of the catalyst composition, or in the range of 5weight percent to 10 weight percent of the catalyst composition.

The inventive catalyst compositions comprise nickel and rhenium ascatalytic metals. In some aspects, the nickel and rhenium are present inthe catalyst portion in a weight ratio in the range of 3:1 to 14:1.

Optionally, the catalyst composition can further comprise one or moreselectivity promoters to enhance selectivity of the catalystcomposition. When present, the selectivity promoter can comprise atleast one element selected from Group IA, Group IIA, Group IIIA, exceptfor boron, Group IVA, Group VA, Group VIA, Group VIIA, Group VIIIA,Group IB, Group IIB, and Group IVB of the Periodic Table. Theselectivity promoter can be present at a promoter/nickel weight ratio of0 to 0.5.

In another aspect, the catalyst composition of the invention can be usedin an amination process. The method includes a step of contacting thecatalyst composition of the invention to promote amination of a reactantto provide an aminated product. In some cases the amination process is atransamination process. In particular, the catalyst composition can beused in a method to promote the transamination of EDA to DETA.

The invention also contemplates methods of making catalyst compositionsthat include a support portion comprising an acidic mixed metal oxidecomprising a transitional alumina and a second metal oxide; and acatalyst portion comprising nickel and rhenium.

Surprisingly, the catalyst composition of the invention showed highactivity and selectivity for the transamination of EDA to DETA. Thecatalyst composition of the invention was active at moderatetemperatures and pressures, and provided good selectivity to the desiredproduct (DETA) while minimizing unwanted cyclic products, includingpiperazine and aminoethylpiperazine. In addition, transaminationreactions involving the catalyst composition can be performed using verylow or no hydrogen as a cofeed. Further, various amines can be fed tothe transamination reaction to provide a variety of ethyleneaminemixtures as products. The inventive catalyst compositions can thusprovide flexibility in terms of reaction conditions and range ofproducts produced.

The various aspects of the invention will now be described in moredetail.

DETAILED DESCRIPTION

The embodiments of the present invention described below are notintended to be exhaustive or to limit the invention to the precise formsdisclosed in the following detailed description. Rather, the embodimentsare chosen and described so that others skilled in the art canappreciate and understand the principles and practices of the presentinvention. The invention is intended to cover all alternatives,modifications, and equivalents that may be included within the scope ofthe present invention as defined by the claims.

Throughout the specification and claims all percentages used herein arein weight percentages, and are based upon the total weight of thecatalyst composition, unless otherwise indicated.

Generally, the invention is directed to catalyst compositions useful intransamination of amine-containing solutions. Catalyst compositions inaccordance with inventive principles include those prepared byincorporating at least two catalytically effective transamination metals(nickel and rhenium) on an acidic mixed metal oxide support. The acidicmixed metal oxide support comprises transitional alumina (aluminum oxide(Al₂O₃)). Such transamination catalyst compositions can provide a higherratio of linear (acyclic) to cyclic products when compared to similarcatalysts that do not contain a transitional alumina-based acidic mixedmetal oxide support.

As discussed herein, the catalyst compositions in accordance withinventive aspects can be utilized to provide the desired linearethyleneamines at high reactant conversion. In addition to providinghigh conversion, the inventive catalyst compositions can provide highselectivity for desired linear products.

Features of the catalyst compositions will now be described in moredetail.

In some aspects, the invention provides a catalyst composition fortransamination of amine-containing solutions, the catalyst compositioncomprising a support portion and a catalyst portion. According to theinventive aspects, the support portion can comprise an acidic mixedmetal oxide. The acidic mixed metal oxide can comprise a transitionalalumina and a second metal oxide. In some aspects of the invention, thetransitional alumina comprises at least 50 weight percent of the supportportion.

Transitional aluminas, or activated aluminas, are described in theEncyclopedia of Chemical Technology, Volume 2, 5th Edition, Kirk-Othmer(1992, page 221 et seq.) as a series of partially hydroxylated aluminumoxides (excluding alpha aluminas which are anhydrous in nature). Ingeneral, as a hydrous alumina precursor is heated, hydroxyl groups aredriven off, leaving a porous solid structure. As the activationtemperature increases through the transitional phases, the crystalstructures become more ordered, thus allowing for identification oftransitional aluminas by x-ray diffraction (hereafter “XRD”). Thesequences of transition are affected not only by the starting materials,but also by the coarseness of crystallinity, heating rates, andimpurities. The following transitions are generally accepted as thetransitions when the starting material is coarse gibbsite in air:

-   -   gibbsite→boehmite→gamma→delta→theta→alpha alumina.        Of the transitional aluminas described above, the delta and        theta phases can be particularly useful as a support portion of        a catalyst composition in accordance with the invention. Other        useful aluminas include mixtures of transitional aluminas and        aluminas such as gamma/theta, gamma/delta, delta/theta,        theta/alpha phases, or combinations thereof.

Transitional alumina carriers may be characterized using an X-raydiffractometer by methods known in the art. The following Table 1 liststhe accepted 2-theta values for the aluminas, as supplied by the JointCommittee on Powder Diffraction Standards International Center for X-RayDiffraction:

TABLE 1 Aluminas gamma 19.58 31.94 37.60 39.49 45.79 60.76 66.76 delta17.65 19.49 21.82 31.14 32.78 34.74 36.96 39.49 45.55 46.54 47.57 50.6760.03 61.35 62.26 64.18 66.76 67.31 73.33 75.37 theta 15.5 16.25 19.5431.509 32.778 34.939 36.743 38.871 39.911 44.856 46.4242 47.5849 50.680351.3931 52.6308 54.5575 56.7218 58.7033 61.2553 62.3387 64.0501 65.371467.4008 alpha 25.5 35.4 38.0 43.6 52.8 57.6 63.05 66.7 68.4In some aspects of the invention, alumina can be employed in its hardestand most stable allotropic state, alpha-alumina (α-alumina) as acombination with a transitional alumina. In other embodiments, aluminacan be employed in its most amorphous state, gamma-alumina, incombination with a transitional alumina. However, in either of thesecases, the transitional forms of alumina are predominant in the aluminamixture.

As noted above, alpha alumina is not considered a transitional phase ofalumina. Rather, alpha alumina is the most thermodynamically stable formof alumina, and once formed, this phase is irreversible. Typically,then, alpha alumina is not present in a significant amount in thesupport portion of the inventive catalyst compositions. Although thecrystallinity of alpha alumina is highly distinctive when compared tothe transitional aluminas, in mixed phases that contain small amounts ofalpha alumina, the amount of alpha alumina present is not easilyquantified. However, due to the extremely low surface areas of alphaaluminas, useful mixed phases containing alpha alumina can be determinedby those which fall within the surface area ranges described herein.

Similarly, while gamma alumina is not considered a transitional phase ofalumina, it may also be present in the support portion. As with alphaalumina, gamma alumina is not typically present in a significant amountin the support portion. Useful mixed phases containing gamma alumina canbe determined by those which fall within the surface area rangesdescribed elsewhere herein.

Generally speaking, transitional aluminas are considered to beintermediate surface area supports. In accordance with the invention,support portions comprising transitional alumina can have surface areasin the range of about 10 m²/g to about 200 m²/g, or about 40 m²/g toabout 180 m²/g, or about 80 m²/g to about 180 m²/g.

As noted above, transitional aluminas can be obtained by heat-treatingtransitional alumina precursor materials such as gibbsite, boehmite, orbayerite to the desired phase transformation temperature. Processing caninvolve heat treatment of a transitional alumina precursor intotransitional alumina, in the form of delta or theta alumina, orcombinations thereof. Other techniques rely upon direct synthesis via awet chemical processing, such as through hydrolysis of aluminumalkoxide.

In another embodiment, transitional alumina material can be formedthrough a seeded processing pathway, such as that described inPCT/US2005/042048 (“Transitional Alumina Particulate Materials HavingControlled Morphology and Processing for Forming Same,” Bauer et al.)and U.S. Patent Publication No. 2008/0003131 A1 (“Transitional AluminaParticulate Materials Having Controlled Morphology and Processing forForming Same,” Bauer et al.). The transitional alumina can be present asa mass of particulate material, composed of particles that may be fullydispersed, partially agglomerated, or fully agglomerate. In the dryform, the particulate material may be in the form of a powder. Thisprocess typically includes providing a boehmite precursor and boehmiteseeds in a suspension, sol or slurry. The suspension, sol or slurry canbe heated treated (such as by hydrothermal treatment) to convert theboehmite precursor into boehmite particulate material formed ofparticles or crystallites. Heat treatment is then carried out to theboehmite particulate material to effect polymorphic transformation intotransitional alumina.

The transitional alumina precursor can be heat treated by calcination ata temperature sufficient to cause transformation into a transitionalphase alumina, or a combination of transitional phases. Typically,calcination or heat treatment can be carried out at a temperaturegreater than about 250° C., but lower than about 1100° C. Attemperatures less than 250° C., transformation into the lowesttemperature form of transitional alumina, gamma alumina, typically willnot take place. At temperatures greater than 1100° C., typically theprecursor will transform into the alpha phase. According to certainembodiments, calcination is carried out at a temperature greater than400° C., such as not less than about 450° C. The maximum calcinationtemperature may be less than about 1050° C. or 1100° C., these uppertemperatures usually resulting in a substantial proportion of thetaphase alumina, the highest temperature form of transitional alumina.

When it is desired to form a substantial content of delta alumina, thetransitional alumina precursor can be calcined at a temperature lowerthan about 950° C., such as within a range of about 750° C. to about950° C. In some embodiments, calcination can be performed attemperatures above about 750° C., or above about 775° C., or above about800° C., to avoid transformation into a predominant gamma phase alumina.

Calcination of the transitional alumina precursor can be carried out invarious environments including controlled gas and pressure environments.Because calcination is generally carried out to effect phase changes inthe precursor material and not chemical reaction, and since theresulting material is predominantly an oxide, specialized gaseous andpressure environments need not be implemented in most cases.

Typically, calcination can be carried out for a controlled time periodto effect repeatable and reliable transformation from batch to batch.Calcination times typically range from about 0.5 minutes to about 60minutes, typically about 1 minute to about 15 minutes.

Generally, as a result of calcination, the alumina material used to formthe support portion is predominantly (more than 50 weight percent)transitional alumina. The precise makeup of transitional alumina phasesmay vary according to different embodiments, such as a blend oftransitional phases. In some embodiments, a predominant amount of aparticular transitional phase can be present, such as at least about 50weight percent, or at least about 60 weight percent, or at least about70 weight percent, or at least about 80 weight percent, of a desiredtransitional phase. In further embodiments, the transitional alumina cancomprise essentially a single phase of transitional alumina (e.g., atleast 95 weight percent, or at least about 98 weight percent, or even upto about 100 weight percent of a single phase of transitional alumina).As discussed herein, the particular phase(s) of transitional alumina canbe determined by XRD.

Illustrative aluminas suitable for inclusion in the support portioninclude delta, theta, gamma/delta, gamma/theta, delta/theta, andtheta/alpha phases. In some embodiments, when alpha alumina is includedin the alumina support portion, it can be present in an amount that isabout 49 weight percent or less. In some embodiments, when gamma aluminais included in the alumina support portion, it can be present in anamount that is about 49 weight percent or less. In still furtherembodiments, the support can include one or more of the followingadditional alumina transitional phases: kappa, eta, rho, chi alumina,and combinations thereof.

In accordance with inventive aspects, the alumina is combined with asecond metal oxide to provide an acidic mixed metal oxide. Illustrativesecond metal oxides include oxides that, when combined with the alumina,can provide sufficient surface acidity to serve as a support portion forthe catalyst composition. Some binary metal oxides are known to havesurface acidity and have been used as solid acid catalysts, such assilica-alumina and alumina-boron oxide. Additional mixed metal oxidesthat may generate surface acidity can be determined using the hypothesisdescribed by Tanabe et al. (A New Hypothesis Regarding the SurfaceAcidity of Binary Metal Oxides, Bulletin of the Chemical Society ofJapan, 47(5):1064-1066 (1974)).

Useful second metal oxides comprise at least one element selected fromGroup IIA, IIIA, IVA, VA, VIA, IIB, IIIB, NB, VB, VIB, VIIB and a rareearth element of the Periodic Table. Illustrative second metal oxides inaccordance with some embodiments include silicon, lanthanum, magnesium,zirconium, boron, titanium, niobium, tungsten and cerium. In someembodiments, the second metal oxide can comprise silicon.

Acidic mixed metal oxides can be prepared by one skilled in the art.Such known preparation methods include coprecipitation of metal salts,sol-gel techniques, ion exchange, mechanical mixing, and incipientwetness or precipitation on metal oxides.

The inclusion of an acidic mixed metal oxide comprising transitionalalumina in the support portion along with the low metal loading canprovide improved catalyst compositions. For example, catalystcompositions in accordance with the invention can include surprisinglylow (e.g., 25 weight percent or less) concentrations of catalyticmetals. Reduction in the amount of catalytic metals required to providethe desired activity and selectivity can provide significantly lowercatalyst costs. Surprisingly, the low-metal loaded catalyst compositionsof the invention demonstrate high activity and selectivity for thetransamination of EDA to DETA. The catalyst is active at moderatetemperatures and pressures and can provide good selectivity to thedesired product (DETA) while minimizing cyclic products such as PIP andAEP.

The acidic mixed metal oxide support portion can be provided in anyconvenient morphology. The shape of the support will typically dependupon the shape required by the particular apparatus used to perform thetransamination reaction. Catalyst compositions can be made on supportsin the form of particles, powders, spheres, extrudates, pellets (cutextrudates), trilobes, quadrilobes, rings and pentarings. In someembodiments, particles can have an elongated morphology, which can bedescribed generally in terms of the particle's aspect ratio. The aspectratio is the ratio of the longest dimension to the next longestdimension perpendicular to the longest dimension. Alternatively,particles can have a platelet-shape, wherein the particles generallyhave opposite major surfaces, the opposite major surfaces beinggenerally planar and generally parallel to each other.

Morphology of the support portion can be further described in terms ofsupport portion size, more particularly, average support portion size.Average support portion size can be described as the average longest orlength dimension of the support material. Average support portion sizecan be determined by taking multiple representative samples andphysically measuring the support material sizes found in representativesamples. Such samples may be taken by various characterizationtechniques, such as by scanning electron microscopy (SEM). In someaspects, the support portion can be provided in the form of anextrudate. Extrudates ranging in diameter of about ⅛″ (3.175 mm) or lesscan be useful, for example in the range of about 1/32″ (0.79375 mm) toabout ⅛″. Another useful form of the support portion is a trilobe.Trilobes having a diameter of about ⅛″ or less can be useful, forexample in the range of about 1/16″ (1.5875 mm) to about ⅛″. Yet anotheruseful support form is a sphere, such as spheres having a diameter of 3mm or less.

In addition to the shape and average support material size, yet anotheruseful way to characterize morphology of the support portion is todescribe the specific surface area of the support portion. The acidicmetal oxide complex can be provided with a range of surface areas(m²/g), as measured by the commonly available BET technique. Accordingto embodiments herein, the support portion can have a relatively highspecific surface area, generally not less than about 10 m²/g, such asnot less than about 40 m²/g, or not less than about 80 m²/g, or not lessthan about 90 m²/g. Since specific surface area is a function ofparticle morphology as well as size, generally the specific surface areaof embodiments can be less than about 200 m²/g, such as less than about150 m²/g, or less than about 100 m²/g. In some embodiments, the surfacearea can be in the range of about 80 m²/g to about 180

Other useful characteristics of the support portion include pore volume(expressed as Hg intrusion values or N₂ values), and water absorption(expressed as a percentage of the dry sample weight). Illustrative porevolume (Hg pore symmetry) ranges are about 0.3 cm³/g to about 1 cm³/g.The percent water absorption is not narrowly critical since the catalystportion is less than 25 percent and can be easily incorporated usingincipient wetness techniques known to one skilled in the art. Anothercharacteristic of the support is the median pore diameter. Again themedian pore diameter is not narrowly critical over the surface area ofthe invention. Additionally, the pore size distribution may be unimodalor multimodal (e.g., bimodal, trimodal, etc.).

The inventive catalyst compositions comprise the support portiondescribed above, and a catalyst portion that comprises nickel andrhenium. Details of the catalyst portion will now be described in moredetail.

Various methods can be carried out for associating/immobilizing themetals of the catalyst portion with the catalyst support. In some modesof practice, the metals of the catalyst portion (nickel and rhenium,used together, or along with one or more other metals) are associatedwith the support portion by impregnation. Impregnation is particularlysuitable for this process, since the lower metal loadings are used.

Although impregnation is one mode of preparing the catalytic support,other methods can be used to associate the catalytic metals with thesupport portion. For example, the metals can be deposited on the supportmaterial by co-precipitation, sol-gel techniques, chemical vapordeposition, or ion exchange. These alternative methods are well known inthe art and can be used for the preparation of the catalyst support ifdesired. In order to describe the process of associating the catalyticmetals with the support, steps of an impregnation method will bedescribed.

As a general matter, the process of depositing the catalytic metals canbe performed to provide a support with a desired amount of the metals.As used herein, the total amount of the catalytic metals in thecompositions is referred to herein as the “catalyst portion,” and theamount of the catalyst portion is expressed as a percentage by weight ofthe catalytic composition. According to the invention, the catalystportion has an amount of metals of 25 weight percent or less of thetotal weight of the catalyst composition. Lower amounts of the catalystportion can be used, such as about 20 weight percent or less of thetotal weight of the catalyst composition. A catalyst composition that is10 weight percent of the catalyst composition has 10 g of a catalystmetal, or a combination of catalyst metals, associated with 90 g of thesupport.

While the invention contemplates inclusion of a catalyst portion havingan amount of metals of 25 weight percent, lower amounts of the catalystportion can be used, such as about 10 weight percent or less of thetotal weight of the catalyst composition. Generally, the catalystportion includes enough of the nickel and rhenium to provide a desiredcatalytic activity when used in an amination process, such astransamination. However, upon review of this disclosure, it will beapparent that lower amounts can be used which provide an economicadvantage while still providing desirable catalytic activity andselectivity. For example, in some modes of practice the amount of metals(nickel and rhenium, used together, or along with one or more othermetals) in the catalyst portion is in the range of about 3 weightpercent to about 20 weight percent of the catalyst composition, or inthe range of about 5 weight percent to about 10 weight percent of thecatalyst composition. Lower (below 3 weight percent) amounts of thecatalyst portion may be used, although it is understood that catalyticactivity may be decreased as well. Although lower catalytic activity maybe acceptable in some catalytic methods, most others would benefit fromhigher levels (i.e., above about 3 weight percent).

The catalyst composition includes a catalyst portion wherein boron isnot present in the catalyst portion, or, alternatively, used only invery small amounts. For example, in many modes of practice the catalystcomposition is prepared without including boron when the catalystportion is immobilized on the catalyst support. Any boron present in thecatalyst portion is desirably less than 1 weight percent, less than 0.5weight percent, or less than 0.3 weight percent.

In some preparations of the catalyst composition, the catalyst portionincludes a mixture of nickel and rhenium in the composition in apredetermined weight ratio. In some cases, the weight ratio of thenickel and rhenium in the composition is in the range of about 3:1 toabout 15:1. In some aspects, nickel is present in an amount in the rangeof about 23 weight percent to about 2 weight percent, and rhenium ispresent in the composition in the range of about 7 weight percent toabout 0.5 weight percent. In some aspects, nickel is present in anamount in the range of about 5 weight percent to about 8.5 weightpercent, and rhenium is present in the composition in the range of about2.5 weight percent to about 1 weight percent. An exemplary catalystportion includes nickel at about 6.8 weight percent and rhenium at about1.8 weight percent.

In some aspects, the selectivity of the catalyst composition may befurther enhanced by the use of metal promoter. The promoter may be ametal (or oxide) which when incorporated into the catalyst compositionfurther enhances the productivity and/or selectivity in the aminationreaction. As an example, metals or metal oxides for use as promoters, inaddition to the nickel and rhenium, are compounds containing elementsselected from Group IA, Group IIA, Group IIIA, Group IVA, Group VA,Group VIA, Group VIIA, Group VIIIA, Group IB, Group IIB and Group IVB ofthe Periodic Table (IUPAC format). Exemplary metals include, forexample, copper, cobalt, chromium, rhodium, iridium, ruthenium, zinc,palladium, platinum, sodium, calcium, magnesium, strontium, lithium,potassium, barium, cesium, lanthanum, tungsten, iron, silver, titanium,manganese, niobium, aluminum, tin and mixtures of these metals. Someparticularly useful metals include magnesium, zinc, niobium, chromium,ruthenium, cobalt, copper, tin and mixtures thereof.

Promoters can be added to the catalyst composition either byco-impregnation with nickel and rhenium or they can be added to thesupport either before or after incorporation of the nickel and rheniumsalts. It should also be understood that the nickel and rhenium need notbe added simultaneously with each other or with the promoter; thepromoter, nickel and rhenium combination can be added in any sequence.Promoters can be added to the catalyst composition at desirable levelswhich are generally no higher than the nickel present in the catalystcomposition on a weight percent basis. In some embodiments, apromoter/nickel ratio of 0 to about 0.5 can be useful.

In some modes of practice the metals of the catalytic portion aredeposited on the support using an incipient wetness technique, oftenreferred to as incipient wetness impregnation (IW or IWI). In thistechnique an active metal precursor (or combination of active metalprecursors) is dissolved in an aqueous or organic solution. Themetal-containing solution (“impregnation solution”) is added to acatalyst support. Often, the impregnation solution is added in a volumethat is the same as the pore volume of the support. Capillary actiondraws the impregnation solution into the pores of the support. Theimpregnated support can then be dried and calcined to drive off thevolatile liquids of the impregnation solution. This process deposits thecatalytic metals on the surface of the support portion.

In some modes of practice, an aqueous solution of a salt of the metal isprepared (the impregnation solution). Since more than one metal is to beimmobilized on the support, the impregnation solution can include amixture of salts of the desired metals. Alternatively, more than oneimpregnation solution can be prepared. The impregnation solution can besaturated with the metal salts, or the metal salts can be used inamounts less than saturation. The concentration of the metal salts inthe impregnation solution can depend on factors such as the desiredamount of metal(s) to be deposited on the support, and the solubility ofthe particular metal salt(s) used in the process.

Organic and inorganic salts of nickel include, but are not limited to,nickel nitrate hexahydrate, nickel formate, nickel acetate tetrahydrate,nickel acetate, nickel chloride, nickel carbonate and the like. Anickel-containing impregnation solution can be prepared containing oneor more of these nickel salts. In some modes of practice, nickel nitrateor nickel formate is used to prepare the impregnation solution.

Precursor salts of rhenium include potassium and ammonium salts.Additionally, perrhenic acid may also be used. A rhenium-containingimpregnation solution can be prepared containing one or both of thesesalts.

In many modes of practice, the one or more metals to be deposited on thesupport are dissolved in a suitable solvent, such as deionized water,for preparation of the impregnation solution.

One or more impregnation solutions can be prepared to provide the typesand total amount of metals to be deposited on the support portion. Sincea lower amount of metal is associated with the support, the total amountof metal can be deposited in a limited number of applications. Forexample, the total amount of metal deposited can be applied in one, two,three, or four applications. Although an impregnation solution can beprepared with a high concentration of metal salt (i.e., a minimal amountof water), in some cases the total amount of the impregnation solutionto be applied may be more than what the alumina support can hold byabsorption. Therefore, in some modes of practice, the impregnationsolution is applied to the support in multiple steps, wherein a portionof the impregnation solution about equal to the absorption volume of thesupport is applied to the support in one application step. Incorporationof additional metal(s) into the support may be further increased bytechniques known to those skilled in the art, such as increasing thetime the support is in contact with the solution.

The impregnation solution can be applied to the support using variousmethods. For example, the solution can be applied processes such as dripapplication, by immersion (e.g., dipping), or by spraying. Duringapplication, the support can be agitated by processes such as mixing,tumbling, stirring, or shaking. Mechanical equipment can be used tofacilitate agitation. Agitation during the application of theimpregnation solution can increase the uniformity of the impregnationsolution applied to the support.

After all or a portion of the impregnation solution is applied to thesupport, the support can be dried. In the drying step, the liquid whichsolvates the metal salt is volatized and removed from the support. Thedrying may be accomplished by any technique that sufficiently evaporatesthe volatile constituents of the impregnation solution. The drying stepcan comprise a calcination step, as further discussed herein. Multipledrying steps can be performed if the impregnation solution is applied inmore than one step. Therefore, an overall process for preparing thecatalyst composition can include multiple steps of disposing theapplication composition, and then drying the impregnated support. Thesteps of depositing and then drying can be performed until all of theimpregnation solution is used.

Typically, the impregnated support is dried at a temperature of above100° C. The elevated temperature can also be accompanied by a reducedpressure environment to accelerate removal of the liquid from thesupport. The support can be dried in air or in the presence of an inertgas, such as nitrogen. Drying is carried out for a period of timesufficient for removal of most or all of the liquid of the impregnationsolution. In some modes of practice, the step of drying is performed fora period of about one hour or more at elevated temperatures.

The process of preparing the catalytic composition can also involve oneor more steps of calcining the support. One or more steps of calciningthe support can be performed in the absence of the catalytic metals, andoptionally in the presence of the catalytic metals, or both.

In some modes of practice, given the high heat of calcination, dryingand removal of the liquid component of the impregnation solution occurs.Therefore, as used herein, calcination of the support meets therequirements of the drying step or steps, which are typically performedfollowing application of the impregnation solution. In addition,calcination can cause conversion of the metal salts into oxides. Thechoice of a particular calcination temperature can depend on thedecomposition temperature of the salts used.

Calcination normally takes place at temperatures below the melting pointof the materials used to form the support portion of the catalyticcomposition. For example, calcination is typically performed in therange of about 200° C. to about 1200° C., and more typically in therange of about 300° C. to about 500° C. A calcination step can take fora period of time in the range of a minute to hours (e.g., two or threeor more hours). Calcination can be carried out in the presence of air,or under inert gas.

In some modes of practice calcination is performed after one or moresteps of applying the impregnation solution. After all of theimpregnation solution has been applied the metal-loaded support can becalcined for a longer period of time to ensure substantial removal ofthe impregnation solution liquid. For example, in some specific modes ofpractice, the impregnation solution is applied to the support in two ormore steps, with calcination at about 340° C. for about one hour in airperformed after each step of applying, with a final calcination at about340° C. for about one hour in air.

Following metal impregnation and calcination, the catalyst compositioncan be reduced, converting the metal oxides produced in the calcinationstep to the reduced metal form. Typically, the metal-containing supportis reduced in the presence of hydrogen. The metal-containing support canbe contacted with hydrogen gas at a temperature that is about in thesame range as that used for calcination. The process of reduction can becarried out from about 30 minutes to about 24 hours, or more.

Following reduction, the catalyst composition can be stabilized withgentle oxidation. Typical stabilizing treatments involve contacting thereduced catalyst composition with oxygen or carbon dioxide. For example,in one mode of practice, the catalyst composition is treated with about1% O₂/N₂. Prior to using in an amination reaction, the catalystcomposition can be activated with hydrogen.

After impregnation and drying/calcination (with optional reduction) thecatalyst composition can optionally be stored or handled in an inertenvironment.

In some aspects, the invention relates to methods for making a catalystcomposition in a manner that reduces or minimizes mass transferresistance for the transamination of the amine-containing solution.Various techniques are known in the art to account for mass transferresistance in supported catalysts. Some illustrative methods foraddressing mass transfer resistance include: adjusting the morphology ofthe catalyst composition, selecting the form of the catalyst composition(e.g., by providing a thin coating of the active catalyst metals on thesurface of the support), and/or the selecting the size of the catalystparticles.

Accordingly, in some embodiments, the morphology of the catalystcomposition can be controlled to reduce or minimize mass transferresistance. For example, PCT Publication No. WO 2006/060206(“Transitional Alumina Particulate Materials Having ControlledMorphology and Processing for Forming Same,” Bauer et al.) describesalumina particulate material that contains particles comprisingtransitional alumina having an aspect ratio of not less than 3:1 and anaverage particle size of not less than about 110 nm and not greater than1000 nm. Various shaped particles are described, including needle-shapedparticles and platy-shaped particles.

In other embodiments, the catalyst portion is deposited on a poroussupport portion so that at least the active catalyst metals are providedin a very thin outer layer or “egg shell” structure, so as to minimizemass transfer resistance for the amine-containing solution. Thiscatalyst structure can also lower the active metal requirement for thecatalyst composition, and/or maximize contact of the active metals withthe amine-containing elements within the reaction solution.

Thus, in accordance with these embodiments, useful catalyst compositiondiameters can be in the range of about 0.8 mm to about 3.1 mm; surfacearea can be in the range of about 10 m²/g to about 200 m²/g;catalytically active metal concentration can be in the range of about 1weight percent to about 25 weight percent, and the catalyst portion canbe provided as a thin outer shell on the support portion.

Methods described in U.S. Pat. No. 5,851,948 can be utilized to create asimilar “egg shell” structure for the present inventive catalystcompositions. For example, the catalytic metals comprising the catalystportion (here, nickel and rhenium) can be added to the support portionas a thin outer layer or shell on the support portion. This smallthickness for the catalyst portion can be influenced by the flowcharacteristics of the nickel and rhenium salts and a suitable carrierliquid solution of an alcohol and water, the porosity and surface areaof the support portion, and the diffusion rate of the active metalliquid solution into the porous support portion. The flowcharacteristics of the nickel and rhenium in the alcohol-water carrierliquid having low surface tension is controlled so as to initially forma “cluster”-type structure of the nickel and rhenium in the carrierliquid on only the outer surface of the support portion. Such “cluster”type structures are formed because of valence differences between ionsof the active nickel and rhenium and molecules of the alcohol carrierliquid, and such larger “clusters” effectively impede penetration of theactive metal into smaller size pores of the support material. During thesubsequent drying, reducing and calcining steps for making the catalyst,the carrier liquid is destroyed and removed so that only the activemetals remain in uniformly dispersed sites in the thin outer “egg-shell”structure on the support portion. Suitable alcohol carrier liquids mayinclude ethanol, methanol and isopropanol.

This technique of depositing an active metal such as nickel and/orrhenium in a thin layer or shell on only the outer surface of thesupport portion advantageously provides a high localized concentrationof the active metals on the catalyst outer surface, where it is readilycontacted by the amine-containing compounds in the reaction solution.Techniques described in U.S. Pat. No. 5,851,948 (Chuang et al.,“Supported Catalyst and Process for Catalytic Oxidation of VolatileOrganic Compounds”) can be instructive in accordance with theseembodiments of the invention.

Catalytic metal can also be deposited on the surface of the supportportion according to techniques described by Komiyama et al.(“Concentration Profiles in Impregnation of Porous Catalysts: Nickel onAlumina,” J. of Catalysis 63, 35-52 (1980)). Utilizing the principlesdescribed by Komiyama et al., radial concentration profiles in thecatalyst compositions can be formed by impregnating the support portionwith aqueous catalytic metal (e.g., nickel) solutions. In accordancewith the present invention, a base can be used with nickel-formate toachieve surface deposition of nickel on alumina supports. Morespecifically, the pH effect on adsorption has been utilized to achievesurface impregnation of nickel by coimpregnating alumina supports withnickel formate (Ni(HCOO)₂.2H₂O) and aqueous ammonia. The result wassurface deposition of the nickel on the alumina supports. Theseprinciples can be further applied to catalyst compositions includingmore than one catalytic metal (e.g., more than one of cobalt, nickel,and/or copper).

In still further embodiments, internal mass transfer resistance can becontrolled by selecting a desirable particle size for the supportportion. As discussed in European Patent Application No. EP 1249440 A1(“Process for Preparing Linear Alkylbenzenes,” Wang et al.), both thecatalyst particle size and porosity can be adjusted to provide a desiredconversion and catalytic stability.

In use, the catalyst composition is added to promote an aminationreaction, such as a transamination process. The amount of catalystcomposition that is used to promote an amination reaction can bedetermined based on one or more of the following factors: the type andamount of reactants, the reactor (reaction vessel) configuration, thereaction conditions (such as temperature, time, flow rate, andpressure), the degree of conversion to a desired product(s), and theselectivity desired (i.e., the ratio of the desired product over anundesired product). The catalyst composition is present in the reactionzone in sufficient catalytic amount to enable the desired reaction tooccur.

The catalyst composition can be used for promoting a transaminationreaction, such as the transamination of a lower aliphatic alkanederivative. In one exemplary mode of practice, the catalyst compositionis used for promoting the transamination of ethylenediamine (EDA) todiethylenetriamine (DETA). The general reaction for the process is shownbelow:

The use of the catalyst composition will now be described with morespecificity for the transamination of EDA to DETA. EDA is a colorlessliquid with an ammonia-like odor and has molar mass of 60.103 g/mol, adensity of 0.899 g/cm³, a melting point of 9° C., a boiling point of116° C. EDA is miscible in water and soluble in most polar solvents.

The products found in the reaction mixture (i.e., the output of thereaction) include transaminated products, with diethylenetriamine (DETA)being the desired product in many modes of practice.Triethylenetetramine (TETA) may be also be found, which results from thefurther reaction of DETA with EDA. Higher order polyamines formed in asimilar manner may also be present in the reaction product mixture.Piperazine is also a transamination product, which is desirably presentin lower amounts in some modes of practice. Aminoethylpiperazine (AEP)is also formed in the reaction mixture. The reaction products may alsoinclude unreacted ethylenediamine, ammonia (which is eliminated in thetransamination reaction), and hydrogen.

The products in the reaction mixture are normally subjected to aseparation step. In the separation step hydrogen and ammonia (the lowmolecular weight compounds) are separated from unreacted ethylenediamineand the transamination products by fractional distillation. Hydrogen andethylenediamine are typically returned to the process.

Operating conditions can be chosen to provide a desired rate ofconversion, which has been shown to affect the selectivity for thedesired product. In particular, conditions are established to provide acertain rate of conversion of EDA, resulting in a desired selectivityfor DETA. For purposes of this invention, “EDA conversion” refers to thetotal weight percentage of reactant (e.g., EDA) lost as a result ofreactions. The conversion can vary depending upon factors such as thereactants, catalyst, process conditions, and the like. In manyembodiments, the conversion (e.g., of EDA) is at least about 10%, anddesirably less than about 50%, and in some modes of practice in therange of about 20% to about 40%. The temperature of reaction can beselected to provide a desired degree of conversion, which is discussedfurther herein. In some modes of practice the desired conversion of EDAis about 25%.

For purposes of the invention, “selectivity” refers to the weightpercentage of converted reactant(s) that form a desired transaminatedproduct, such as DETA. In some modes of practice the percent selectivityto DETA is about greater than 50%, greater than 65%, such as in therange of about 65% to about 75%. Like conversion, selectivity will varybased upon factors including the conversion of the reactant(s), feedreactants, catalyst, process conditions, and the like.

The mixture of reaction products can also be defined in terms of theweight ratio of two products in the mixture. Typically, ratios usefulfor assessing the quality of the reaction mixture are of a desiredproduct to an undesired product (e.g., DETA/PIP), or desired product toa different desired product (e.g., DETA/TETA). For example, the mixtureof reaction products can be described in terms of the weight ratio ofDETA to piperazine (DETA/PIP) at an EDA conversion of 25%. In some modesof practice, the catalyst composition of the invention is used in atransamination reaction to provide a DETA/PIP ratio of about 9:1 orgreater, about 10:1 or greater, about 11:1 or greater, about 11.5:1 orgreater, or about 12.0:1 or greater, such as in the range of about 9:1to about 13:1, or about 10:1 to about 13:1, or about 11:1 to about 13:1,or about 11.5:1 to about 13:1, or about 12:1 to about 13:1.

The weight ratio of TETA to PIP, may also be useful for determining theselectivity of the reaction. In some modes of practice, the catalystcomposition of the invention is used in a transamination reaction toprovide a TETA/PIP ratio at an EDA conversion of 25% of about 0.75:1 orgreater, about 0.8:1 or greater, or about 0.9:1 or greater, 1:1 orgreater, about 1.1:1 or greater, about 1.2:1 or greater, or about 1.3:1or greater, or about 1.4:1 or greater, such as in the range of about0.75:1 to about 1.5:1, about 0.8:1 to about 1.5:1, about 0.9:1 to about1.5:1, or about 1:1 to about 1.5:1.

Using the catalyst composition of the present invention, transaminationcan be performed using any suitable method and reaction equipment. Forexample, transamination can be carried out using a continuous process, asemi-continuous process, a batch-wise process, or a combination of theseprocesses. The transamination process using the catalyst composition ofthe present invention can be carried out in a conventional high-pressureequipment with a heating feature. The equipment can have one or morefeatures which cause movement of the reactants and/or catalysts in theequipment, such as an agitator or pump. Various reactor designs can beused, such as a stirred-tank, fixed-bed, slurry, or fluid-bed reactors.The reactors can be designed for liquid-phase, gas-phase, multi-phase orsuper-critical conditions.

In some modes of practice, the reactant (e.g., EDA) is provided to thereaction bed that includes the catalyst composition as a stream, thestream having continuous flow. The reactant feed can be upflowing ordownflowing. Design features in the reactor that optimize plug flow canalso be used. Effluent from the reaction zone is also a streamcomprising the unreacted components of the feed stream (such as EDA) andthe reaction products (DETA). In some modes of practice, a liquid EDA isestablished in an upflow direction into the catalyst bed. In some modesof practice, a flow rate is established to provide a space velocity inthe range of about 5 gmol/hr/kg catalyst to about 50 gmol/hr/kgcatalyst, with an exemplary space velocity of about 15 gmol/hr/kgcatalyst.

The transamination reaction can be carried out with little or nohydrogen. However, as an optional component, hydrogen gas can be presentduring the transamination reaction. In some cases, hydrogen mayfacilitate the production of the reaction product, and inhibit or reducepoisoning of the catalyst. If desired, hydrogen can be included prior toand/or within the transamination reactor in an amount sufficient toaffect catalyst activity and product selectivity. Exemplary amounts ofhydrogen include 0.001 to 10.0 mole % based on liquid feed. A source ofhydrogen gas can optionally be combined with the ethyleneamines sourceand fed to the transamination reactor.

Optionally, ammonia can be used affect selectivity by inhibitingundesired reactions.

Generally, reaction temperatures for transamination process fall withinthe range of about 110° C. to about 180° C., and in desired modes ofpractice a reaction temperature in the range of about 130° C. to about160° C. are used. The temperature can be varied throughout the reactionprocess, and may fluctuate up to about 30%, or up to about 20% of thestarting temperature. The temperature of reaction can be selected toprovide a desired rate of conversion. In many modes of practice, thetemperature is chosen to provide a relatively low rate of conversion.

Typical reaction pressures range from about 200 psig to about 2000 psig,about 400 psig to about 1000, and in some desired modes of practice thepressure is about 600 psig.

The catalyst compositions of the present invention can be used in themethods described in any one of the Assignee's applications listed andtitled as follows:

U.S. Provisional Application Ser. No. 61/195,404 entitled “A PROCESS TOSELECTIVELY MANUFACTURE DIETHYLENETRIAMINE (DETA) AND OTHER DESIRABLEETHYLENEAMINES VIA CONTINUOUS TRANSAMINATION OF ETHYLENEDIAMINE (EDA),AND OTHER ETHYLENEAMINES OVER A HETEROGENEOUS CATALYST SYSTEM”, filedOct. 6, 2008, in the names of Petraitis et al.;

U.S. Provisional Application Ser. No. 61/195,405 entitled “METHODS FORMAKING ETHANOLAMINE(S) AND ETHYLENEAMINE(S) FROM ETHYLENE OXIDE ANDAMMONIA, AND RELATED METHODS”, filed Oct. 6, 2008, in the names of DavidDo et al;

U.S. Provisional Application Ser. No. 61/195,412 entitled “METHODS OFMAKING CYCLIC, N-AMINO FUNCTIONAL TRIAMINES”, filed Oct. 6, 2008, in thename of Stephen W. King; and

U.S. Provisional Application Ser. No. 61/61/195,454 entitled “METHOD OFMANUFACTURING ETHYLENEAMINES”, filed Oct. 6, 2008, in the names ofPetraitis et al.

Further, reagents and/or methods described in these co-pendingapplications can be incorporated by reference to further describe theuse of the catalyst composition of the present invention.

Aspects of this application are related to the following Assignee'sapplications listed and titled as follows:

U.S. Provisional Patent Application Ser. No. 61/195,434 entitled “LOWMETAL LOADED, ALUMINA SUPPORTED, CATALYST COMPOSITIONS AND AMINATIONPROCESS”, filed Oct. 6, 2008, in the names of King et al.

The invention will now be described with reference to the followingnon-limiting Examples.

EXAMPLES

The following Examples are included for illustrative purposes only, andthe scope of the invention is in no way limited to the use of theparticular Ni/Re catalyst compositions set forth in the Examples or tothe use of EDA as the lower aliphatic alkane derivative being aminated.Similar results can be achieved using other catalyst compositions andderivatives consistent with the scope of the invention as describedherein.

Unless otherwise noted, catalyst compositions were prepared using thefollowing generalized procedure. Precursor salts of the metals (nickeland rhenium) were dissolved in 70-80° C. water to form an impregnationsolution. The final volume of the impregnation solution was adjusted toequal the adsorption volume required for the number of times that thesupport was impregnated, and the quantities of the precursor salts werethose calculated to give the metal compositions provided in theExamples. In each case the support was impregnated to incipient wetnessby the addition of the appropriate amount of impregnation solution andgently agitated until all the liquid was adsorbed. The sample was thenplaced in a muffle furnace and calcined in air for one hour at 340° C.or as otherwise specified in the Examples. When the support had cooled,additional impregnations were performed until all of the solution hadbeen added. A calcination step at 340° C. was done after eachimpregnation.

Those skilled in the art will readily appreciate that impregnation withthe impregnation solution can optionally be performed in one, two, fouror more incipient wetness applications, as dictated by such variables asthe solubility of the precursor sales, the porosity of the support to beimpregnated, and the desired weight loading of the metal.

Prior to use, the catalyst compositions were reduced in hydrogen byramping the temperature at 3° C./minute to 230° C., holding at thistemperature for one hour, and then ramping at 3° C./minute to 340° C.,and holding for 3 hours, or as otherwise specified in the Examples. Thecatalyst compositions were allowed to cool under hydrogen to ambienttemperature, after which they were stabilized by adding a flowing streamof 1% oxygen in nitrogen until the exotherm ceased. At no time was theexotherm allowed to exceed about 70° C.

The catalyst compositions were tested as extrudates; spheres, pellets ortrilobes (as specified in the Examples) in a small tubular reactor forthe transamination of ethylenediamine (EDA) to diethylenetriamine(DETA), as described below.

A tubular reactor consisting of a 316-stainless steel tube having aninside diameter of 1.75 cm and an overall length of about 76 cm was usedfor the transamination of the ethyleneamine(s) feed. Typically, 50 gramsof a catalyst composition were packed into the central portion of thetube using glass beads to fill the void spaces between the catalystparticles. Glass wool plugs were used to hold the catalyst bed in place.

In each case, the reduced and stabilized catalyst composition wasactivated by passing approximately 45 slph of hydrogen through the bedfor approximately 18 hours at 180° C. and atmospheric pressure. Thereactor system was then generally brought to 600 psi and the temperaturedesignated in the tables while still under hydrogen. A motor valve atthe outlet of the reactor was used to control the system pressure.

When at the designated reaction conditions, the ethyleneamine(s) andoptionally ammonia, was pumped into the reactor at an ethyleneamine(s)feed rate of approximately 15 gmole/kg cat/hr. Prior to passing througha preheater, hydrogen was introduced into the ethyleneamine(s) stream ata flow rate of about 3 slph. After passing through the preheater, whichwas maintained at reactor temperature, the mixture was passed into thereactor over the catalyst bed composition via upward flow. Downstream ofthe pressure-control valve, the reaction mixture was passed into areceiver where the product was collected in a semi-batch fashion. Theliquid product was condensed in the receiver at ambient temperature,allowing the ammonia and hydrogen to flash off. The condensed sample wasthen analyzed by capillary gas chromatography. Each catalyst compositionwas tested over a temperature range of 130-210° C. to determine theeffect of conversion on selectivity.

Each catalyst composition was typically tested at three to sevendifferent temperatures, over the range of 145°-175° C., to determine theeffects of conversion on selectivity. The conversion and selectivitydata thus obtained were subjected to curve fitting, and the resultantequation used to calculate selectivities at 25% EDA conversion. These25% conversion values are used in Examples 1 and 2 for purposes ofcatalyst selectivity comparisons at the same EDA conversion. Pressureand the EDA, NH₃ and hydrogen feed rates were held constant throughout.

The temperature required for 25% EDA conversion was determined for eachcatalyst. The data illustrates that the process in accordance withaspects of the invention yields an amine composition with DETA/PIPratios as high as 14.20.

Example 1

In each of Examples 1A-1U, catalyst compositions containing 6.8 weightpercent Ni, 1.8 weight percent Re on alumina-silica supports were usedfor the transamination of EDA to DETA. For Examples 1W, the catalystcomposition included 6.8 weight percent Ni and 0.9 Re on analumina-silica supports. For Example 1X, the catalyst compositionincluded 6.8 weight percent Ni and 0.5 Re on an alumina-silica support.The catalysts had varying support compositions, surface areas, shapesand diameter sizes, as noted in Table 2. The catalyst compositions weretested in the tubular reactor by the above described method.

The results, shown in Table 2, demonstrate that catalyst compositionsaccording to some aspects of the present invention can provide both highactivities and high DETA selectivities. The data demonstrate that Ni/Reon an acidic mixed metal oxide (e.g., transitional alumina/silica)support can be a preferred catalyst composition for selectivity to DETA(represented as the ratio of DETA/PIP) via a transamination reaction. Inaddition, the data illustrate that addition of boron to the catalystcomposition can have a negative impact on DETA selectivity (see Example1V). Further, the data show using a 1/16″ support versus a ⅛″ support(see Example 1A and Example 1U) can improve selectivity (represented asthe ratio of DETA/PIP). Also the use of a 1/16″ trilobe (Example S) gavethe best selectivity (DETA/PIP). These results may be due to minimizingdiffusional resistances.

Comparative Example 2

Catalyst compositions 2A, 2H, and 2I were prepared in accordance withthe methods described in Example 1, in accordance with some aspects ofthe invention.

Examples 2B through 2G were obtained from commercial sources forcomparative purposes. As indicated in the Table 3, Example 2B was RaneyNi, and Examples 2C-2G included high Ni or high Co catalysts on varioussupports. The support of Example 2H included gamma alumina/silicasupport, provided as a ⅛″ extrudate. The support of Example 2I includeda non-transitional state alumina (silica/alumina) as part of thesupport, in the form of a 1/16″ extrudate. As shown in Table 3, resultsdemonstrate that activities (EDA conversion) and DETA selectivities(DETA:PIP) for the comparative samples were inferior to those obtainedwith Example 2A (which was prepared in accordance with aspects of theinvention). Improved selectivity was observed with lower metal supportsprepared in accordance with the invention, as compared to commerciallyobtained Example 2B-2G.

Other embodiments of this invention will be apparent to those skilled inthe art upon consideration of this specification or from practice of theinvention disclosed herein. Various omissions, modifications, andchanges to the principles and embodiments described herein may be madeby one skilled in the art without departing from the true scope andspirit of the invention which is indicated by the following claims. Allpatents, patent documents, and publications cited herein are herebyincorporated by reference as if individually incorporated. The patents,patent documents and publications cited herein are provided solely fortheir disclosure prior to the filing date of the present application.Nothing herein is to be construed as an admission that the inventor isnot entitled to antedate such disclosure by virtue of prior invention.

TABLE 2 Carrier SA % Sel to Example Metals Carrier (m²/g) Temp, ° C.DETA DETA/PIP 1A Ni/Re (6.8/1.8 wt. %) alumina (theta)/silica (80:20)1/16″ extrudate 151 134 69.50 12.41 1B Ni/Re (6.8/1.8 wt. %) gammaalumina ⅛″ extrudate 250 159 66.21 6.48 1C Ni/Re (6.8/1.8 wt. %) thetaalumina 1/16″ extrudate 127 160 67.15 9.36 1D Ni/Re (6.8/1.8 wt. %)gamma alumina 1/16″ trilobe extrudate 250 158 65.99 6.39 1E Ni/Re(6.8/1.8 wt. %) gamma alumina 1/16″ sphere 160 161 68.60 9.16 1F Ni/Re(6.8/1.8 wt. %) transitional alumina ⅛″ trilobe extrudate 145 159 65.487.29 1G Ni/Re (6.8/1.8 wt. %) transitional alumina ⅛″ pellet 145 15768.29 9.91 1H Ni/Re (6.8/1.8 wt. %) transitional alumina 1/16″ sphere120 160 66.45 9.02 1I Ni/Re (6.8/1.8 wt. %) transitional alumina 1/16″trilobe extrudate 80 159 67.37 10.36 1J Ni/Re (6.8/1.8 wt. %) alumina(gamma)/silica (90:10) ⅛″ CDS extr 245 165 58.61 3.35 1K Ni/Re (6.8/1.8wt. %) alumina (delta)/silica (90:10) ⅛″ CDS extr 134 151 68.31 9.88 1LNi/Re (6.8/1.8 wt. %) high purity silica 1/16″ extrudate 140 147 65.106.90 1M Ni/Re (6.8/1.8 wt. %) silica/alumina (98:2) 1/16″ extrudate 68148 66.91 8.16 1N Ni/Re (6.8/1.8 wt. %) gamma alumina ⅛″ extrudate 250159 66.21 6.48 1O Ni/Re (6.8/1.8 wt. %) high purity zirconia 1/16″extrudate 98 175 60.58 4.60 1P Ni/Re (6.8/1.8 wt. %) titania 1/16″extrudate 45 170 64.91 8.18 1Q Ni/Re (6.8/1.8 wt. %) delta/theta mixedalumina 1.6 mm sphere 77 162 66.86 9.64 1R Ni/Re (6.8/1.8 wt. %)delta/theta mixed alumina with 1.2% La2O3 103 162 66.77 8.49 1S Ni/Re(6.8/1.8 wt. %) alumina (delta/theta)silica (70:30) 1/16″ trilobe 90 14469.30 14.20 1T Ni/Re (6.8/1.8 wt. %) alumina (theta)/silica (80:20) ⅛″extrudate 107 136 67.09 10.48 1U Ni/Re (6.8/1.8 wt. %) alumina(theta)/silica (80:20) ⅛″ extrudate 149 140 70.11 11.85 1V Ni/Re/B(8.0/2.1/1.7 wt. %) alumina (theta)/silica (80:20) ⅛″ extrudate 107 14868.06 8.76 1W Ni/Re (6.8/0.9 wt. %) alumina (theta)/silica (80:20) ⅛″extrudate 107 146 68.34 11.63 1X Ni/Re (6.8/0.5 wt. %) alumina(theta)/silica (80:20) ⅛″ extrudate 107 150 66.65 7.84 1Y Ni/Re (6.8/1.8wt. %) alumina (theta)/silica (50:50) ⅛″ extrudate 147 144 69.97 11.211Z Ni/Re (6.8/1.8 wt. %) zirconia/silica (75:25) 1/16″ extrudate 130 14768.44 9.26

TABLE 3 % Sel to Example Metals Carrier Temp, ° C. DETA DETA/PIP 2ANi/Re (6.8/1.8 wt. %) alumina (theta)/silica (80:20) 1/16″ extrudate 13469.50 12.41 2B Ni (50 wt. %) Grace-Davison Raney Ni 5886 fixed bed,Ni—Al 8-12 mesh 186 57.70 5.33 2C Ni (50 wt. %) Sud-Chemie C46-8-03 Nion alumina, 1/16″ trilobe 147 67.03 9.40 2D Ni (48 wt. %) EngelhardNi-0750-E, Ni on gamma Alumina, ⅛″ extrudate 144 63.82 5.92 2E Co/Zr(54/2 wt. %) Sud-Chemie G-67 on Kieselguhr, ⅛″ extrudate 138 61.17 5.162F Co (14.5 wt. %) DeGussa 14.5% Co on gamma alumina 1 mm extrudate 14866.19 8.26 2G Ni (50 wt. %) Sud-Chemie C46-7-03, Ni on silica-alumina(2:1), 1/16″ trilobe 137 66.88 10.17 2H Ni/Re (6.8/1.8 wt. %) alumina(gamma)/silica (90:10) ⅛″ CDS extr 165 58.61 3.35 2I Ni/Re (6.8/1.8 wt.%) silica/alumina (98:2) 1/16″ extrudate 148 66.91 8.16

1. A catalyst composition comprising: (a) a support portion comprisingan acidic mixed metal oxide comprising a transitional alumina and asecond metal oxide, wherein the second metal oxide has a weightpercentage that is less than the weight percentage of alumina; and (b) acatalyst portion comprising nickel and rhenium, wherein: the catalystportion is deposited as a shell structure on the support portion in amanner effective to provide a localized concentration of nickel andrhenium on an outer surface of the catalyst composition, the catalystportion is 25 weight percent or less of the catalyst composition, thecatalyst portion comprises nickel in an amount in the range of 2 to 20weight percent, based upon total catalyst composition weight, andwherein boron constitutes less than 1 weight percent of the catalystportion.
 2. The catalyst composition according to claim 1, wherein thetransitional alumina comprises delta alumina.
 3. The catalystcomposition according to claim 2, wherein the transitional aluminafurther comprises one or more of gamma, theta or alpha alumina.
 4. Thecatalyst composition according to claim 1, wherein the transitionalalumina comprises theta alumina.
 5. The catalyst composition accordingto claim 4, wherein the transitional alumina may optionally furthercomprise one or more of gamma or alpha alumina.
 6. The catalystcomposition according to claim 1, wherein the second metal oxidecomprises at least one oxide selected from the group consisting of anoxide of silicon, lanthanum, magnesium, zirconium, boron, titanium,niobium, tungsten and cerium.
 7. The catalyst composition according toclaim 6, wherein the second metal oxide comprises silicon.
 8. Thecatalyst composition according to claim 1, wherein the support portioncomprises the second metal oxide in an amount in the range of 5 weightpercent to less than 50 weight percent, based upon the weight of thesupport portion.
 9. The catalyst composition according to claim 1,wherein the support portion is an extrudate having an elongatemorphology diameter of ⅛ inches (3.175 mm) or less.
 10. The catalystcomposition according to claim 1, wherein the support portion is asphere having a diameter of 3 mm or less.
 11. The catalyst compositionaccording to claim 1, wherein the support portion is a trilobe having adiameter of ⅛ inches (3.175 mm) or less.
 12. The catalyst compositionaccording to claim 1, wherein the catalyst portion is 20 weight percentor less of the catalyst composition.
 13. The catalyst compositionaccording to claim 1, wherein the nickel and rhenium are present in thecatalyst portion in a weight ratio in the range of 3:1 to 14:1.
 14. Thecatalyst composition according to claim 1, wherein the compositionfurther comprises a selectivity promoter that is present at apromoter/nickel weight ratio of 0.5:1 or less.
 15. The catalystcomposition according to claim 1, wherein the catalyst composition is anextrudate with an elongate morphology and has a diameter in the rangefrom 0.8 mm to 3.1 mm.
 16. The catalyst composition according to claim1, wherein there is no boron in the catalyst portion.